Electrical connection.



. PATENTED MAY 5, 1908. G. H. JACOB & J. L. HAGADORN.

ELECTRICAL CONNECTION.

APPLICATION FILED JULY 14. 1906.

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UNI ED STATES PATENT OFFICE.-

GEORGE H. JACOB AND JOHN L. HAGADORN, OF DETROIT, MICHIGAN.

' ELECTRICAL CONNECTION.

Specification of Letters Patent.

Application filed July 14, 1906. Serial .No. 326,239.

Patented May 5, 1908.

To all whom it may. concern.-

Be it known that We, GEORGE H. JAooB and JOHN L. HAGADORN, citizens ofthe United States, residing at Detroit, in the county of Wayne andStateof Michigan, have invented new and useful Improvements in ElectricalConnections, of which the following is a specification.

The invention relates to an improvement in electrical connectionsdesigned primarily for use in providing an extension circuit closer forcall bell or other signal systems.

4 The main object of the present'invention is the provision of a flushplug for providing electrical connection with the fixed socket,

the plug being constructed to carry the conductors of the extension andto insure proper electrical contact of said conductors with theconductors of the socket, whereby to form a continuous circuit by theintroduction of the plug into the socket.

Another object of the invention is the provision of means whereby theextension and conductors are secured in fixed relation to the plug.

Another object of the invention is the provision of means whereby theinsertion of the flush plug Within the socket is rendered impossibleexce t in a predetermined position of the plug, w ereby to insure theproper electrical connections andavoid short circuiting at the point ofconnection.

The invention will be described in the following specification,reference being had particularly to the accompanying drawings, in whichr g Figure l is a perspective view illustrating the improved connection,the plug and socket being shown separated, Fig. is a vertical section ofthe socket, Fig. 3 a vertical section of the plug, Fig. 4 a perspectiveof one of the plug sections, Fig. 5 is a detailed perspective of theinsulating strip, Fig. 6 is a vertical sec tional view of the insulatinsleeve, Fig. 7 is an enlarged sectionaldetai illustrating the means forsecuring the extension circuit conductors to the insulating strip, Fi 8is a transverse section showing a mod' ed form of connection between theplug and socket.

Referring particularly to the drawings, it will be noted that ourimproved connectlon is to be shown as primarily designed to provide apush button extension for call bell circuits, or other signalingdevices, wherein the socket ordinarily utilized to receive and sup- 8port the ushlbutton, is used for the reception of a ush plug of peculiartype andcarrying fiexible conductors, whichconductors by theintroduction of the plug provide in effect an extension of the circuitso that the bell or other signaling device may be sounded from anydesired point distant from the usual closer.

In the preferred details of structure the socket comprises a floor plate1 and a depending barrel 2 ofinsulating material, the barrel beingdiametrically reduced at its u per end to provide an extension 3 snugyseating within an opening 4 in the plate 1,

whereby the wall opening through the socket is of insulating materialthroughout its length. Spring plates 5 and 6 are securedto diametricallyopposite points of the barrel, their free ends depending below thebarrel and being bent inwardly and terminating in downwardly projectingli ps 7 disposed within the plane of the socket opening. The circuitconductors 8 and 9, which include the source of energy and the alarm,are secured in a preferred manner tothe spring strips 5 and 6, so thatthe circuit is broken only by the normal separation of the lips 7 of therespective contacts 5 and 6.

The socket above described is of the ordinary ty 'e used in callbellisystems, and

articulary designed to be secured in the oor and adapted to contain apush button which on depression would bridge the break between thespring contacts 5 and 6 and close the circuit, with the effect to soundthe alarm. Such s'ockets are well known and largely used for call bellsystems in houses, being ordinarily positioned in the floor beneath thetable or in the wall for convenient access. It is at times desirable,however, to extend the circuit to provide for operating the signal at apoint distant from the socket, and with this particular object in viewwe have devised the extension'forming the sub ject matter of thisinvention.

The flush plug designed for cooperation cross section having a body 12and a reduced extension 13 projecting from the upper end of the body,the relative small dimension of the extenslon providing a shoulder 14 atthe junction of said extension and body. The

the

lower end of the body 12, or that end op 0- site the extension 13 isgradually reduce in sectional dimension to provide a pointed end 15which when the sections are assembledprovide the plug with an invertedconoidal point to provide for the proper insertion between the li s 7 ofthe spring contacts of the socket, aso so that said plug may be insertedin the socket through a rug or carpet without damaging the weave. The

extension 13 is threaded at 16, and formed on its, convex surface with alongitudinaly extending groove 17, opening through the upperedge of thesection13 and continuinsulating material 21. is arranged between theplane surfaces of the sections when they are assembled, said stripextending the full width of said surface and being, of sufiicientthickness to provide the desired insulation. By preference theinsulating strip 21 'extends above the upper end of the extensions 13 ofthe plug sections, as at 22. Theside edges of theextension 22 areslightly grooved at 22 in order that the conductorswhich are connectedto said flush plug can be tied with thread to said insulating strip sothat any strain on the-metallic connections between the conductors andthe flush plug will be eliminated.

In assembled form the plug is of cv lindrical shape'with a reducedcylindrica extension at the upper end, the latter being formed withdiametrically opposed grooves and exteriorly threa'd'ed' The conductors2'3 and 24 of the extension circuit are stripped of their insulation fora desired distance and respectively seated in one .of the grooves 17 ofeach section of the flush plug, and tied around the groove of the thatof t insulatin treme en ally, as at 25, and seated 1n the groove exten-21 at groove in 22, the exsion 18 formed in the shoulder 14 of thesection. An insulating sleeve 26 is interiorly threaded for connectionwith the threads 16 of the lug extension; 13, said sleeve being prefera1g of an external diameter equal to e connected body members of the plugsections. The sleeve 26 is designed to, seat snugly upon. the shoulder14 of the plug, in, which position it will-bind the conductors of theextension circuit within the grooves 17 and at the same time overlie andsecure the laterally bent ends of said conductors in the grooves 18. The'ioop end of the Wall of the interior 0 ening of the sleeve is free ofthe threaded ormation, to provide a plane porstrip of t e conductorbeing bent later-- -sse,s11

tion 18 which serves to hear u on and force the conductors 23 and' 24mto t e groeves as the sleeve 1s screwed to-its seat.

The conductors are thus secured relative to the plug one of t e plugsections.

preferably of greater length than the extena sion 13 of the plug, andthe projection 22 of the insulating strip 21 is utlhzed to divide theslee e opening above the plug extension into two chambers for thepassage of the conductors 23 and 24, effectively insulating saidconductors from eachother, as will be obvious. I

Owing to the possibility of so introducing the plug within the socketthat one of the sections of the plug 10 will enga e both spring contacts5 and 6 and thereby c ose the signa circuit at this olnt we provide oneof the plug sections wit a groove 27 extending longitudinally of thebody 12 thereof and opening througha portion of the point 15 of saidsection. For cooperation with said groove we secure in the wall of thebarrel 2 a screw 28 formed with a. plain reduced end 29, which When thescrew is in operative position is designed to enter the groove 27 in theblock and guide the latter in its movement toward the spring contacts.The relative arrangement of the groove 27 and screw 28 is such that incooperation the plug is so guided that one section, as 10, will engageone spring contact, while the other section, as 11, engages the otherspring contact.

It is, of course, tobe understood that the conductors 23 and 24 may beof any length desired and that they are, at the terminals opposite theplug provided with any usual gr preferred form of push button or other0.;- cuit closer.

The extension described is of simple construction, and-owing to the reltive arrangement of parts possibility o accidentally closing the alarmcircuit on the introduction of the lug is absolutely avoided;furthermore, t e extension circuit conductors are fixedly secured to theplug in a manner to guard against their accidental disconnection,

' extendan electric circuit for any purpos as. 'it is obvious that theconductors 23 and 24 may lead to a lamp, a motor, or other objectrequiring the use of electric current, and in this particular connectionit is to be parwhile at the vsame time permitting their a ticularlynotedthat the body of the respective plug sections is less in length than thedistance from the plate 1 to the free ends of the contacts 5 and 6'sothat it is im ossible in the use of the plug described for t e oper atorto receive the current while introducing the plug, as the exposedmetallic portions of' position the spring character of the contactsmetal or insulating materialis contemplated.

the plug will of necessity be below the plate 1 before said sectionsengage the spring contacts of the socket.

In use the plug is preferably inserted so that the upper edge of thesleeve 26 is flush with the surface of the plate 1, the relative lengthsof the parts being such that when the plug is in this position the lips7 of the spring contacts engage the cylinder plain surface of therespective sections, in which form an effective aid in holding the plugagainst accidental displacement. The lip 7' may, if preferred, beslightly concaved in transverse section, as at 30, whereby to moresnugly embrace the cylindrical surface of the plug sections, as will beevident.

The metallic portions of the plug and socket are preferably of brass andthe insulating sections of hard rubber, though it is to be understoodthat the use of any desired In Fig. 8 is illustrated a slightly modifiedconstruction for guiding the flush plug inits longitudinal movement inthe socket. In this form of the parts the barrel wall is integrallyformed wit an inwardly extending pro jection 31, which is designed tocooperate with the groove 27 in the plug, and guide the plug in movementin an obvious manner.

, Having thus described the invention, what is claimed as new, is

1. The combination-with aso'cket including spaced contacts of a signalcircuit, of a plug and conductors, said plug comprising independentsections insulated from each other, and means for securing therespective conductors in electrical contact with the respectivesections, said means serving to secure the respective sections together.

2. A flush plug for extension circuits comprising duplicate sections, astrip of insulation arranged between the sections, circuit conductors,and means for removablysecuring the conductors to the respectivesections, said means serving to secure the sections together and supportthe strip of insulation therebetwee'n.

3. A plug for extension circuits comprisingduplicate sections ofsemicylindrical form in section, means for securing the sectionstogether, a strip of insulation disposed lengthwise between thesections, an extension provided on'each section, a right angle grooveformed in the section to receive the appropriately formed terminal ofthe-conductor, and means for securing said conductors within thegrooves.

4. A plug for extension circuits comprising duplicate sections ofsemicylindrical form in section, means for securing the sectionstogether, a strip of insulation disposed lengthwise between thesections, an extension provided on each section, a right angle grooveformed in the section to receive the appropriately formed terminal ofthe conductor, and a sleeve designed to removably engage the extensionandbind the conductors in the a sleeve designed to removably engage theextension and bind the conductors inthe respective grooves, said sleevebeing of greater length than .the extension to provide an insulatedhousing for a portion of the conductors beyond the extension.

6. A plug for extension circuits comprising duplicate sections ofsemicylindrical form in section, means for securing the sectionstogether, a strip of insulation disposed lengthwise between thesections, an extension provided on each section, a right angle grooveformed in the section to receive the appropriately formed terminal ofthe conductor, and a sleeve designed to-removably engage the extensionand bind the conductors in the respective grooves, said sleeve being ofgreater length than the extension to provide an insulated housing for aportion of the conductors beyond the extension, the insulating stripbetween the sections extending within sai housing and separating therespective conductors.

7. The combination with a socket including diametrically opposed spacedcontacts, and a plug comprising insulated sections designed forrespective engagement with the respective contacts, and means forguiding the plug within the socket to ro erly. dispose the sectionsthereof with re ation -to the contact, said means serving to limit themovement of the plug within the socket to dispose the upper end of theplug flush with the uppler surface of the socket.

. 8. T e combination with a socket including diametricallyopposed spacedcontacts,

and a plug comprlsing insulated sections designed for respectiveengagement with the respective contacts, a screw seated in the soccentral opening therein, the plug being formed with a groove to receivethe screw in the longitudinal movement of the plug, whereby to guide theplug ,to properly dispose the sections thereof with relation to thespring contact, said groove and screw cooperating to limit the movementof the plug within the socket to dispose the upper end of the plug flushwith the upper surface of the socket.

9. The combination with a socket including spaced contacts of a si nalcircuit, of a plug and conductors, the p ug including inet andprojecting Within the plane of the dependent sections and a removablesleeve designed to bind the sections together and engage and secure theconductors to the respective sections of the plu i r 10. The combinationwi'si a socket including spaced contacts of a signal circuit, of a lugand conductors, said lug comprising independent sections forme withconductor receiving grooves, and a sleeve having threaded connectionwith the socket and overlying the grooves, a portion of the sleeve beinglain to force the conductors into the grooves in the operation of thesleeve.

11. A lug for extension circuits comprising dup icate sections ofsemicylin'drical form, "means for securing the sections together,circuit conductors secured to the res ective sections and a strip ofinsulation isposed between the sections, said strip being groovedtoreceive and hold a flexible connection adapted to be Wound about theconductors and the strip.

In testimony whereof, we afiix our signatures in presence of twowitnesses.

GEORGE H. JACOB. JOHN L. HAGADORN.

Witnesses:

ED H. CARLISLE, NELLIE B. OARLIsLE.

